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A145932
Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a tee 1,1 1,2 1,3 2,2 in any orientation.
0
1, 1, 1, 5, 20, 85, 428, 3123, 34838, 454719, 8335296, 187056538, 6169076015, 247329264689, 14010937295624, 978281276679416, 99281241941019762, 12290336204514423117
OFFSET
1,4
EXAMPLE
Maximal 8 X 8 example
.1.1.1.0.0.1.1.1
.0.1.0.0.0.0.1.0
.0.0.0.1.1.1.0.1
.1.0.0.0.1.0.1.1
.1.1.0.1.0.0.0.1
.1.0.1.1.1.0.0.0
.0.1.0.0.0.0.1.0
.1.1.1.0.0.1.1.1
CROSSREFS
Sequence in context: A341920 A045499 A358518 * A026661 A099014 A219672
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 25 2008
STATUS
approved